Galen,
My $0.02! Take it with a grain of salt.
I find that when I ride, sometimes, the portion of the binding that you showed gets filled snow, to the point that it turns into ice. Couple that with some more snow on your heel, compression of the binding, and vibration during your ride. Overtime, if not paid attention to, it might do something similar to what you just showed.
Although, different from your issue, I too have a small gripe with TD2 std. which I posted here last month and no one replies.
Regards,
Cristan